Quantitative and nondestructive determination of residual stress for SiO₂ thin film by laser-generated surface acoustic wave technique

Abstract

The laser-generated surface acoustic wave (SAW) technique is a promising method to measure the mechanical properties of thin films quickly and nondestructively. Residual stress is inevitable during the processing and manufacturing of integrated circuits, which will have a major impact on the physical and mechanical properties of the thin film materials and cause deterioration to the structural strength. In this study, the SAW technique based method is proposed for quantitative and nondestructive measuring the residual stress in the nanostructured films. The method is verified by the experiment measuring the SiO2 films in the thickness range of 100 to 2000 nm. The experimental procedures, including signal excitation, reception and processing, are described in detail. By matching the SAW experimental dispersion curve with the calculated theoretical dispersion curve containing the residual stress, the residual stress of the SiO2 films along [110] and [100] crystallographic orientation of the Si wafer is successfully quantified. The determination results are ranged from -65.5 to 421.1 MPa and the stress value increases as the film thickness decreases, revealing the residual stress of the SiO2 film is compressive. Meanwhile, the conventional substrate curvature method as a comparison is used to verify the correctness and feasibility of the proposed SAW method for the residual stress determination.

Nondestructive Determination of Young's Modulus of Interconnecting Thin Films by a Broadband Surface Acoustic Wave‐Interdigital Transducer

“…To obtain precise NDT results, it is vital to obtain an accurate SAW dispersion curve. [31][32][33] There are several approaches for determining the dispersion of the phase velocity from the normal displacement. In this study, a slant stack transformation was developed to calculate the phase velocity of SAW, which is rapid and enables the dispersion curve to be revealed with remarkable accuracy.…”

“…Furthermore, varying the unknown SAW velocity v yields a 2D array of time-velocity correlations. This transformation process is given by Equation (33).…”

Development of Wide-Angle Short-Wave Pass Thin Film Based on the Ultra-Thin Silicate Glass

“…They can also remove benign tumors, regenerate nerves, reduce inflammation, relieve jaw pain, and even whiten teeth. The benefits of laser dentistry include less pain and discomfort, and a faster healing time, with only minor damage to the gums and teeth [14,15]. There is also a reduced need for sutures and local anesthesia.…”

Nondestructive Measurement by One-Port Surface Acoustic Wave Resonator for Accurate Evaluation of Film Thickness

“…In our previous research, by using SAW technique, multiple mechanical properties of films have been successfully measured. [18][19][20] At present, various sensors based on SAW technology provide great potential for sensor applications due to their excellent performance. The most prominent advantage of SAW sensors is fast and easy to operate.…”